A wireless microphone is a microphone without a physical cable connecting it directly to the sound system. Wireless microphones are also known as radio microphones or cordless microphones. A wireless microphone has a small, battery-powered radio transmitter in the microphone body, which transmits the audio signal from the microphone by radio waves to a nearby receiver unit, which IS connected to the sound system. Wireless microphones are widely used in the entertainment industry, television broadcasting, and public speaking to allow public speakers, interviewers, performers, and entertainers to move about freely while using a microphone to amplify their voices.